/*********************************************************************
*              SEGGER MICROCONTROLLER GmbH & Co. KG                  *
*        Solutions for real time microcontroller applications        *
**********************************************************************
*                                                                    *
*        (c) 2014-2014 SEGGER Microcontroller GmbH & Co. KG          *
*                                                                    *
*       Internet: www.segger.com Support: support@segger.com         *
*                                                                    *
**********************************************************************
----------------------------------------------------------------------
File        : SEGGER_RTT_printf.c
Purpose     : Replacement for printf to write formatted data via RTT
---------------------------END-OF-HEADER------------------------------
*/
#include "SEGGER_RTT.h"
#include "SEGGER_RTT_Conf.h"

/*********************************************************************
*
*       Defines, configurable
*
**********************************************************************
*/

#ifndef SEGGER_RTT_PRINTF_BUFFER_SIZE
#define SEGGER_RTT_PRINTF_BUFFER_SIZE (64)
#endif

#include <stdlib.h>
#include <stdarg.h>


#define FORMAT_FLAG_LEFT_JUSTIFY   (1 << 0)
#define FORMAT_FLAG_PAD_ZERO       (1 << 1)
#define FORMAT_FLAG_PRINT_SIGN     (1 << 2)
#define FORMAT_FLAG_ALTERNATE      (1 << 3)

/*********************************************************************
*
*       Types
*
**********************************************************************
*/

typedef struct {
	char* pBuffer;
	int   BufferSize;
	int   Cnt;

	int   ReturnValue;

	unsigned RTTBufferIndex;
} SEGGER_RTT_PRINTF_DESC;

/*********************************************************************
*
*       Function prototypes
*
**********************************************************************
*/
int SEGGER_RTT_vprintf(unsigned BufferIndex, const char * sFormat, va_list * pParamList);

/*********************************************************************
*
*       Static code
*
**********************************************************************
*/
/*********************************************************************
*
*       _StoreChar
*/
static void _StoreChar(SEGGER_RTT_PRINTF_DESC * p, char c) {
	int Cnt;

	Cnt = p->Cnt;
	if ((Cnt + 1) <= p->BufferSize) {
		*(p->pBuffer + Cnt) = c;
		p->Cnt = Cnt + 1;
		p->ReturnValue++;
	}
	//
	// Write part of string, when the buffer is full
	//
	if (p->Cnt == p->BufferSize) {
		if (SEGGER_RTT_Write(p->RTTBufferIndex, p->pBuffer, p->Cnt) != p->Cnt) {
			p->ReturnValue = -1;
		}
		else {
			p->Cnt = 0;
		}
	}
}

/*********************************************************************
*
*       _PrintUnsigned
*/
static void _PrintUnsigned(SEGGER_RTT_PRINTF_DESC * pBufferDesc, unsigned v, unsigned Base, int NumDigits, unsigned FieldWidth, unsigned FormatFlags) {
	static const char _aV2C[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
	unsigned Div;
	unsigned Digit = 1;
	unsigned Number;
	unsigned Width;
	char c;

	Number = v;

	//
	// Get actual field width
	//
	Width = 1;
	while (Number >= Base) {
		Number = (Number / Base);
		Width++;
	}
	if ((unsigned)NumDigits > Width) {
		Width = NumDigits;
	}
	//
	// Print leading chars if necessary
	//
	if ((FormatFlags & FORMAT_FLAG_LEFT_JUSTIFY) == 0) {
		if (FieldWidth != 0) {
			if (((FormatFlags & FORMAT_FLAG_PAD_ZERO) == FORMAT_FLAG_PAD_ZERO) && (NumDigits == 0)) {
				c = '0';
			}
			else {
				c = ' ';
			}
			while ((FieldWidth != 0) && (Width < FieldWidth--)) {
				_StoreChar(pBufferDesc, c);
				if (pBufferDesc->ReturnValue < 0) {
					return;
				}
			}
		}
	}
	//
	// Count how many digits are required by precision
	//
	while (((v / Digit) >= Base) | (NumDigits-- > 1)) {
		Digit *= Base;
	}
	//
	// Output digits
	//
	do {
		Div = v / Digit;
		v -= Div * Digit;
		_StoreChar(pBufferDesc, _aV2C[Div]);
		if (pBufferDesc->ReturnValue < 0) {
			break;
		}
		Digit /= Base;
	} while (Digit);
	//
	// Print trailing spaces if necessary
	//
	if ((FormatFlags & FORMAT_FLAG_LEFT_JUSTIFY) == FORMAT_FLAG_LEFT_JUSTIFY) {
		if (FieldWidth != 0) {
			while ((FieldWidth != 0) && (Width < FieldWidth--)) {
				_StoreChar(pBufferDesc, ' ');
				if (pBufferDesc->ReturnValue < 0) {
					return;
				}
			}
		}
	}
}

/*********************************************************************
*
*       _PrintInt
*/
static void _PrintInt(SEGGER_RTT_PRINTF_DESC * pBufferDesc, int v, unsigned Base, unsigned NumDigits, unsigned FieldWidth, unsigned FormatFlags) {
	unsigned Width;
	unsigned Number;

	Number = (v < 0) ? -v : v;

	//
	// Get actual field width
	//
	Width = 1;
	while (Number >= Base) {
		Number = (Number / Base);
		Width++;
	}
	if (NumDigits > Width) {
		Width = NumDigits;
	}
	if ((FieldWidth > 0) && ((v < 0) || ((FormatFlags & FORMAT_FLAG_PRINT_SIGN) == FORMAT_FLAG_PRINT_SIGN))) {
		FieldWidth--;
	}

	//
	// Print leading spaces if necessary
	//
	if ((((FormatFlags & FORMAT_FLAG_PAD_ZERO) == 0) || (NumDigits != 0)) && ((FormatFlags & FORMAT_FLAG_LEFT_JUSTIFY) == 0)) {
		if (FieldWidth != 0) {
			while ((FieldWidth != 0) && (Width < FieldWidth--)) {
				_StoreChar(pBufferDesc, ' ');
				if (pBufferDesc->ReturnValue < 0) {
					return;
				}
			}
		}
	}
	//
	// Print sign if necessary
	//
	if (v < 0) {
		v = -v;
		_StoreChar(pBufferDesc, '-');
		if (pBufferDesc->ReturnValue < 0) {
			return;
		}
	}
	else if ((FormatFlags & FORMAT_FLAG_PRINT_SIGN) == FORMAT_FLAG_PRINT_SIGN) {
		_StoreChar(pBufferDesc, '+');
		if (pBufferDesc->ReturnValue < 0) {
			return;
		}
	}
	//
	// Print leading zeros if necessary
	//
	if (((FormatFlags & FORMAT_FLAG_PAD_ZERO) == FORMAT_FLAG_PAD_ZERO) && ((FormatFlags & FORMAT_FLAG_LEFT_JUSTIFY) == 0) && (NumDigits == 0)) {
		if (FieldWidth != 0) {
			while ((FieldWidth != 0) && (Width < FieldWidth--)) {
				_StoreChar(pBufferDesc, '0');
				if (pBufferDesc->ReturnValue < 0) {
					return;
				}
			}
		}
	}

	//
	// Print number without sign
	//
	_PrintUnsigned(pBufferDesc, v, Base, NumDigits, FieldWidth, FormatFlags);
}

/*********************************************************************
*
*       Public code
*
**********************************************************************
*/
/*********************************************************************
*
*       SEGGER_RTT_vprintf
*
*  Function description
*    Stores a formatted string in SEGGER RTT control block.
*    This data is read by the host.
*
*  Parameters
*    BufferIndex  Index of "Up"-buffer to be used. (e.g. 0 for "Terminal")
*    sFormat      Pointer to format string
*    pParamList   Pointer to the list of arguments for the format string
*
*  Return values
*    >= 0:  Number of bytes which have been stored in the "Up"-buffer.
*     < 0:  Error
*/
int SEGGER_RTT_vprintf(unsigned BufferIndex, const char * sFormat, va_list * pParamList) {
	char c;
	SEGGER_RTT_PRINTF_DESC BufferDesc;
	int v;
	unsigned NumDigits;
	unsigned FormatFlags;
	unsigned FieldWidth;
	char acBuffer[SEGGER_RTT_PRINTF_BUFFER_SIZE];

	BufferDesc.pBuffer = acBuffer;
	BufferDesc.BufferSize = SEGGER_RTT_PRINTF_BUFFER_SIZE;
	BufferDesc.Cnt = 0;
	BufferDesc.RTTBufferIndex = BufferIndex;
	BufferDesc.ReturnValue = 0;

	do {
		c = *sFormat++;
		if (c == 0) {
			break;
		}
		if (c == '%') {
			//
			// Filter out flags
			//
			FormatFlags = 0;
			do {
				c = *sFormat;
				switch (c) {
				case '-': FormatFlags |= FORMAT_FLAG_LEFT_JUSTIFY; sFormat++; break;
				case '0': FormatFlags |= FORMAT_FLAG_PAD_ZERO;     sFormat++; break;
				case '+': FormatFlags |= FORMAT_FLAG_PRINT_SIGN;   sFormat++; break;
				case '#': FormatFlags |= FORMAT_FLAG_ALTERNATE;    sFormat++; break;
				default:  goto FilterFieldWidth;                   break;
				}
			} while (1);
			//
			// filter out field with
			//
		FilterFieldWidth:
			FieldWidth = 0;
			do {
				c = *sFormat;
				if (c < '0' || c > '9') {
					break;
				}
				sFormat++;
				FieldWidth = FieldWidth * 10 + (c - '0');
			} while (1);

			//
			// Filter out precision (number of digits to display)
			//
			NumDigits = 0;
			c = *sFormat;
			if (c == '.') {
				sFormat++;
				do {
					c = *sFormat;
					if (c < '0' || c > '9') {
						break;
					}
					sFormat++;
					NumDigits = NumDigits * 10 + (c - '0');
				} while (1);
			}
			//
			// Filter out length modifier
			//
			c = *sFormat;
			do {
				if (c == 'l' || c == 'h') {
					c = *sFormat++;
					continue;
				}
				break;
			} while (1);
			//
			// Handle specifiers
			//
			switch (c) {
			case 'c': {
						  char c0;
						  v = va_arg(*pParamList, int);
						  c0 = (char)v;
						  _StoreChar(&BufferDesc, c0);
						  break;
			}
			case 'd':
				v = va_arg(*pParamList, int);
				_PrintInt(&BufferDesc, v, 10, NumDigits, FieldWidth, FormatFlags);
				break;
			case 'u':
				v = va_arg(*pParamList, int);
				_PrintUnsigned(&BufferDesc, v, 10, NumDigits, FieldWidth, FormatFlags);
				break;
			case 'x':
			case 'X':
				v = va_arg(*pParamList, int);
				_PrintUnsigned(&BufferDesc, v, 16, NumDigits, FieldWidth, FormatFlags);
				break;
			case 's':
			{
						const char * s = va_arg(*pParamList, const char *);
						do {
							c = *s++;
							if (c == 0) {
								break;
							}
							_StoreChar(&BufferDesc, c);
						} while (BufferDesc.ReturnValue >= 0);
			}
				break;
			case 'p':
				v = va_arg(*pParamList, int);
				_PrintUnsigned(&BufferDesc, v, 16, 8, 8, 0);
				break;
			case '%':
				_StoreChar(&BufferDesc, '%');
				break;
			}
			sFormat++;
		}
		else {
			_StoreChar(&BufferDesc, c);
		}
	} while (BufferDesc.ReturnValue >= 0);

	if (BufferDesc.ReturnValue > 0) {
		//
		// Write remaining data, if any
		//
		if (BufferDesc.Cnt != 0) {
			SEGGER_RTT_Write(BufferIndex, acBuffer, BufferDesc.Cnt);
		}
		BufferDesc.ReturnValue += BufferDesc.Cnt;
	}
	return BufferDesc.ReturnValue;
}

/*********************************************************************
*
*       SEGGER_RTT_printf
*
*  Function description
*    Stores a formatted string in SEGGER RTT control block.
*    This data is read by the host.
*
*  Parameters
*    BufferIndex  Index of "Up"-buffer to be used. (e.g. 0 for "Terminal")
*    sFormat      Pointer to format string, followed by the arguments for conversion
*
*  Return values
*    >= 0:  Number of bytes which have been stored in the "Up"-buffer.
*     < 0:  Error
*
*  Notes
*    (1) Conversion specifications have following syntax:
*          %[flags][FieldWidth][.Precision]ConversionSpecifier
*    (2) Supported flags:
*          -: Left justify within the field width
*          +: Always print sign extension for signed conversions
*          0: Pad with 0 instead of spaces. Ignored when using '-'-flag or precision
*        Supported conversion specifiers:
*          c: Print the argument as one char
*          d: Print the argument as a signed integer
*          u: Print the argument as an unsigned integer
*          x: Print the argument as an hexadecimal integer
*          s: Print the string pointed to by the argument
*          p: Print the argument as an 8-digit hexadecimal integer. (Argument shall be a pointer to void.)
*/
int SEGGER_RTT_printf(unsigned BufferIndex, const char * sFormat, ...) {
	va_list ParamList;

	va_start(ParamList, sFormat);
	return SEGGER_RTT_vprintf(BufferIndex, sFormat, &ParamList);
}
/*************************** End of file ****************************/
